On Tuesday, Monsanto suffered a serious blow when six jurors in a San Francisco federal court unanimously decided that Roundup (glyphosate), the world’s most widely-used herbicide, was likely a “substantial factor” in the genesis of 70-year-old Edwin Hardeman’s non-Hodgkin’s lymphoma, a cancer of the lymph system.

Hardeman said he sprayed Roundup on his 56-acre property for 26 years, according to the San Francisco Chronicle.

The world’s largest producer of controversial genetically modified crop seeds (GMOs), Monsanto was acquired for $66 billion in June by German agricultural and pharmaceutical giant Bayer AG, creating a mega-corporation controlling 25 percent of the global seed and pesticide market.

In phase two of the trial, which began Wednesday, jurors will decide whether Monsanto is liable and for how much, according to Reuters.

This is the first time Roundup has been presumed carcinogenic in a federal court. In August, a California jury reached a similar decision regarding former school groundskeeper Dwayne “Lee” Johnson’s non-Hodgkin’s lymphoma. Johnson was awarded $289 million in damages, which was reduced to $78 million and is now on appeal.

Why is this one San Francisco trial such a big deal?

The Hardeman case is one of three bellwether trials, basically, test cases for about 760 similar cases that have been consolidated and transferred from around the country in a process known as “multidistrict legislation.” The results are used to shape the judicial process for the remaining cases.

In a statement Tuesday, Bayer wrote, “We are disappointed with the jury’s initial decision, but we continue to believe firmly that the science confirms that glyphosate-based herbicides do not cause cancer.”

More than 10,000 Roundup cancer cases are currently pending in state and federal courts.

Monsanto is finally having its day in court.

Many days, it appears.